Tablet has an issue with rapid charging

I have a Venue 11 Pro that won’t rapid charge with the original Dell charging brick. I even tried another Dell Venue 11 brick, so that’s not the issue . The battery discharges while in use, even while plugged in. I checked the BIOS, and it’s only charging at 3W instead of 25W. It now has to charge overnight to reach 100%, where it it used to fully charge in a couple of hours. I brought it to IFIX New York, and they want $250 to repair it — just labor, no parts need replacing, apparently. It’s not worth $250, and it’s long out of warranty. Has anyone had this problem and knows a cheap fix, or a NYC repair shop that isn’t going to gouge? Other than that issue, it’s in perfect condition and works well. Thank you.